1. Field of the Invention
The present invention relates to pressurized fluid systems in general, and, more particularly, to a pressure vessel assembly of a pressurized fluid system including at least one fluid-pressure accumulator.
2. Description of the Prior Art
In conventional integrated pressurized fluid systems the recovered energy is normally accumulated in hydraulic fluid accumulators. The latter are of known technology and, in comparison with the other recovery and accumulation arrangements, such as flywheel accumulators and electrochemical batteries, they are more flexible in use, notably in connection with a vehicular transmission to which they are connected. On the other hand they remain less efficient in terms of mass and volume and consequently raise serious problems for fitting onto motor vehicles. In addition to penalizing the energy savings obtained, these problems of dead weight and bulk lead to high costs linked either with the hydraulic fluid accumulator itself or, mainly, with the modifications that have to be made to the vehicle to fit the accumulator. The result is that the motor vehicles equipped with the hydraulic fluid accumulator are no longer standard in any way and are therefore much more expensive to produce and maintain and that, furthermore, the equipment used for this installation cannot be transposed to another vehicle or modulated in size, which increases the overall cost of such an installation.
Moreover, the conventional metal shell fluid accumulators are rather heavy. Furthermore, in some applications, including mobile applications, such as regenerative drive systems of motor vehicles, the fluid accumulators are exposed to excessive vibrations and operate in particularly harsh environments. In order to address these issues, some fluid accumulators are fabricated from a composite material in order to significantly reduce the weight of the fluid accumulators and to protect them in the harsh environments. However, the composite shell accumulators require extra consideration with regards to mounting and vibration. The composite outer shells of the fluid accumulators also tend to expand under pressure. This expansion is most apparent along longitudinal axes of the accumulators. Moreover, the need exists to package and protect the sensitive composite shelled hydro-pneumatic accumulators against physical damage, shock and vibration in the mobile applications. Also there is a need to provide a protective structure for personnel and/or equipment in the vicinity of the accumulators in the event of a failure of the pressure shell.
Accordingly, it is the intent of this invention to overcome these shortcomings of the prior art by providing a pressure vessel assembly housing fluid accumulators in order to protect them against physical damage, shock, vibration and linear expansion in the mobile applications, and capable of being fitted to various types of pressurized fluid systems, including motor vehicles equipped with hydraulic regenerative drive system.